The Most Lethal Sin – The Hardening of Your Heart

The Most Lethal Sin The Hardening o fYour HeartFor it was of the Lord to harden their hearts, that they should come against Israel in battle, that [Israel] might destroy them utterly, and that without favor, as the Lord commanded Moses. (Joshua 11:20)

Modernists and liberal theologians have constantly condemned the conquest of Canaan as the most brutal and cruellest wars in the all the history of Israel. In their endeavors to bring the people of God into disrepute, they obtusely sympathize with the victims and brazenly denounce the Israelite.

Notwithstanding all their criticism, one thing stands out brilliantly in the pages of Scripture describing Joshua’s war expeditions in Canaan-the final consummation of God’s righteous judgments after a very lengthy time of patience and long suffering.

The nations in Canaan who, at the command of God had to be utterly destroyed, had ample time to repent of their grievously idolatrous ways (among other things, child sacrifices which is equal to today’s abortion of babies). Not a single city or it’s inhabitants, be it the king or his subjects, were unaware of the mighty miracles God performed in the midst of His people. In fact, several accounts are given in the book of Joshua that substantiate the first-hand knowledge they had of God’s dealings with Israel.

Rahab the harlot was in awe of God’s mighty deeds when she recounted how He led them dry shod through the Red Sea when they came out of Egypt, and their victorious battles against the kings of the Amorites (Joshua 2:9-13). God’s judgments on Egypt and their false gods convinced her that Israel’s God was the one and only true God in the heavens above and the earth beneath.

Her plea for mercy that they spare her father and mother, brothers and sisters when Jericho was to be destroyed, earned her an honourable place in the hall of the heroes of faith in the eleventh chapter of Hebrews. She responded with humility to the righteous judgments of God and she and her whole family were saved. All the other inhabitants of Jericho callously ignored the fact that God’s patience and long suffering means salvation and refused to honour Him as the only true God in the universe (2 Peter 3:15).

Similarly the Gibeonites made a wily covenant with Joshua because they heard of his fame and all that He had done in Egypt (Joshua 9:9). One of the most baffling mysteries in Scripture is man’s callous resistance to God’s loving-kindness, long suffering and the unsearchable richness of His mercies. Why does the majority of the human race refuse to respond to God’s outstretched arms of grace and love?

The answer is given by the prophet Isaiah in his book, chapter 26 verses 9 and 10. Isaiah declares with great fortitude, “only when Your judgments are in the earth will the inhabitants of the world learn righteousness. Though favour be shown to the wicked, yet he does not learn righteousness; in the land of uprightness he deals perversely and refuses to see the majesty of the Lord.”

The profound meaning of these words becomes clear when we look at the tremendous blessings God bestowed on the inhabitants of Canaan before Israel conquered the land. It is a well-known fact that it was a land that flowed with milk and honey. The enormity of one cluster of grapes the Israelite spies brought back with them from the valley of Eschol, bears witness to the great blessings God showered on the peoples in Canaan.

They enjoyed these blessings for more than 400 years while Israel was suffering under the yoke of Egyptian cruelty. Yet they refused to see the majesty of the Lord. They did not learn righteousness, neither through the blessings nor the judgments of the Lord of which they heard in Egypt. They hardened their hearts and continued to crouch before their idols. What a devastatingly repugnant thing to do!- to harden your heart in the face of the most tender-hearted and gracious God whose blessings are showered on the entire earth.

How can God harden the heart of a sinner?

Several questions ensue from the historical account given thus far-“How can a God whose compassion and tender-hearted kindness endure forever, harden the hearts of people?”; “When does God harden the heart of a sinner?” “Is there any hope left for those whose hearts He has hardened?” “How can one possibly believe that a God of love can harden a person’s heart?”

Headstrong willfulness on the part of the unrepentant sinner supplies the key to all these questions. A case in point is Amenhotep II, the Pharaoh who refused to let the Israelite go when God sent Moses to him. To some people the hardening of Pharaoh’s heart as well as the hearts of the Egyptians (Exodus 14:17) is an enigma that incites them to harden their own hearts and resist God’s gracious mercies.

However, they seem to overlook the fact that Pharaoh hardened his own heart six times before God began to harden his heart. He was merely affirming Pharaoh’s defiant and willful obstinacy. God was in effect giving Pharaoh completely over to the hardness of his own heart when all possible avenues to bring him to his senses had been fully exhausted.

The same principle is found in the New Testament where Paul writes, “They perish because they refused to love the truth and so be saved. For this reason God sends them a powerful delusion so that they will believe the lie and so that all will be condemned who have not believed the truth but have delighted in wickedness (2 Thessalonians 2:10 & 11).

Foolhardy resistance to God and the richness of His mercies is extremely dangerous. The eternal truth that God is slow to anger and abounding in love is a great comfort to those who respond to His love and compassionate mercies, and who reverently fear Him (Psalm 103:8-13). Equally true is the fact that the calloused in heart who persistently harden their hearts will undoubtedly experience the full fury of His righteous judgments.

The destruction of a third part of the human race will have absolutely no effect on those who remain, for “the rest of the men which were not killed by these plagues yet repented not of the works of their hands, that they should not worship devils, and idols of gold, and silver, and brass, and stone, and of wood: which neither can see, nor hear, nor walk:Neither repented they of their murders, nor of their sorceries, nor of their fornication, nor of their thefts. (Revelation 9:20).


Today, if you hear His voice,

do not harden your hearts.”

(Hebrews 4:7)

for tomorrow might just be too late.

Take heed: the road to hell is paved with good intentions.

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Tom (Discerning the World)

Tom Lessing is the author of the above article. Discerning the World is an internet Christian Ministry based in Johannesburg South Africa. Tom Lessing and Deborah Ellish both own Discerning the World. For more information see the About this Website page below the comments section.

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MarthinaTom (Discerning the World)Martin HoranSharon Recent comment authors
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Mat 24:11 And many false prophets shall rise, and shall deceive many. Mat 24:12 And because iniquity shall abound, the love of many shall wax cold. We are witnessing the rise of the false prophets.…  Read more »

Martin Horan

Absolutely incredible piec of writing, Debs. (Great one Thomas, as Sharon above seems to indicate you wrote it. It applies to all of us though. From what I’ve read, the Edomites are today’s “Palestinians”–who only…  Read more »


I listned to a podcast from Prof Leighton Flowers from He also talked about the Pharoa’s hardening heart. So God is hardening his heart in order to bring about the Passover to demonstrate His…  Read more »


Thank you for taking your time to reply. I am going to take some time and go through all the Scripture references in your reply. When I first started reading you blog it was quite…  Read more »